Went from 30’s to 32’s MPG’s went up?

[dck82]

I have a Base 2.3 7MT with about 4K on the odometer that I recently swapped the steelies off of for Big Bend wheels and tires. I have calibrated the speedo. What’s throwing me is my mpgs have gone up. Not considerably but I expected to take a small hit. Right now I’m averaging 23.9 according to the computer. That’s up from just under 23 with the steelies. My first thought is the tires are the same width and the alloys from the BB could be lighter than steelies, though I’m not sure. Does all this seem plausible? I’m also assuming because the speedometer has been calibrated than the mpg reporting should be accurate. I filled up a couple of days ago and I said I had 398 miles until E. I’m sorry I just don’t believe it.

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[EveryDayBronco]

I have a set of bb wheels and tires for the base model (still waiting) and I was hoping to see an improvement in mpg so I'm thrilled by your results.

I think the tire weighs 5 or 6 lbs more but I don't know the difference in the weight of the wheel. If the weigh is same or lighter for the larger 32" dia then I'd expect an improvement in mpg.

The way to check is to ask 2-door manual trans big bend (non sas) owners what mpg they're getting!

 

[BottleShark]

I'm going 40's to save gas lol

 

[thesocalexplorer]

I wouldn't be surprised if the narrow big bend pizza cutters are the reason for great MPG. I've been running mine at 36PSI cold since I bought the rig, and am always pleasantly surprised with highway MPG. Long highway drives can easily bring 26-27MPG on the MPG trip gauges.

 

[EveryDayBronco]

I wouldn't be surprised if the narrow big bend pizza cutters are the reason for great MPG. I've been running mine at 36PSI cold since I bought the rig, and am always pleasantly surprised with highway MPG. Long highway drives can easily bring 26-27MPG on the MPG trip gauges.

Can you guys post pics of your 2 door factory bid bend wheeled broncos (non sas)?

 

[Bronc_Bronc]

In addition to weight and surface drag (amount of tire contacting the road), maybe the 32s just hit a sweet spot on gear ratio at 65 MPH. I don't do maths well though.

 

[dck82]

I wouldn't be surprised if the narrow big bend pizza cutters are the reason for great MPG. I've been running mine at 36PSI cold since I bought the rig, and am always pleasantly surprised with highway MPG. Long highway drives can easily bring 26-27MPG on the MPG trip gauges.

Thank you for the reply. Glad to see I’m not an outlier. I thought for sure something was off.

 

[dck82]

Can you guys post pics of your 2 door factory bid bend wheeled broncos (non sas)?

before and after.

 

[MnLakeBum]

FWIW, the laws of physics apply to all Broncos. They are all large, heavy, boxy, and get crappy fuel economy until they give us a diesel or hybrid. My wife’s 2018 Range Rover weighs 5,050 pounds and runs on 32.5” tires. The 3.0L Ford Lion powering it gives us 443 ft/lbs of torque, a 7,700 pound towing capacity, and an average of 29.1 mpg over 74,000 miles with some of those miles pulling a boat or jet skis.

 

[Lakelife36]

FWIW, the laws of physics apply to all Broncos. They are all large, heavy, boxy, and get crappy fuel economy until they give us a diesel or hybrid. My wife’s 2018 Range Rover weighs 5,050 pounds and runs on 32.5” tires. The 3.0L Ford Lion powering it gives us 443 ft/lbs of torque, a 7,700 pound towing capacity, and an average of 29.1 mpg over 74,000 miles with some of those miles pulling a boat or jet skis.

A. Cool story bro
B. lb-ft

 

[Lakelife36]

I have a Base 2.3 7MT with about 4K on the odometer that I recently swapped the steelies off of for Big Bend wheels and tires. I have calibrated the speedo. What’s throwing me is my mpgs have gone up. Not considerably but I expected to take a small hit. Right now I’m averaging 23.9 according to the computer. That’s up from just under 23 with the steelies. My first thought is the tires are the same width and the alloys from the BB could be lighter than steelies, though I’m not sure. Does all this seem plausible? I’m also assuming because the speedometer has been calibrated than the mpg reporting should be accurate. I filled up a couple of days ago and I said I had 398 miles until E. I’m sorry I just don’t believe it.

Did you have a chance to calculate your consumption by hand before switching? Even if you didn't I would start now and see how close the computer is. The assumption that the computer is correct because the speedo has been calibrated may not be valid - for example my bigman is constantly off by ~0.5L/100km.

 

[dck82]

Did you have a chance to calculate your consumption by hand before switching? Even if you didn't I would start now and see how close the computer is. The assumption that the computer is correct because the speedo has been calibrated may not be valid - for example my bigman is constantly off by ~0.5L/100km.

I haven’t started yet, but I got the Fuelly app. I’m going to start tracking on my next fill up.

 

[mountainbronco]

Roll resistance of the two tires are likely different.
Roll resistance influenced by rubber compound, tread style, tire width and pressure.

Also, to compare mpg without a wind and speed consideration on a specific stretch makes it hard to ensure you drove the same with both sets....

 

[JT58Bronc]

I would say if the tire/wheel combo is lighter then yes, it would lead to better gas mileage. I had a 2013 Civic SI that the original wheels were removed and narrow tires with steelies installed. I drive it that way for awhile until I got new wheels ordered. I was getting like 35 MPG. The new wheels were aluminum and much heavier and wider than the steelies. MPG went down to about 29.

BTW you are doing well on the MPG. You must really know how to drive to get the best MPG. I know as I get 21.7 average in my 2.7 2 door Sasquatch.

 

[Paul Gagnon]

Taller tires reduce your cruising RPMs.

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